Methods for fusing a fiber termination

ABSTRACT

Aspects of the disclosure are drawn to methods for producing a fused connector termination. An exemplary method may include setting a specification requirement to be met by the fused connector termination and applying an amount of heat to a proximal region of an unfused connector termination. The proximal region of the unfused connector termination may include an inner optical fiber coaxially positioned within an outer ferrule, and applying the amount of heat may at least partially fuse the optical fiber to the outer ferrule to form an at least partially fused connector termination. The method may also include imaging the proximal region of the at least partially fused connector termination and determining, based on the imaging, whether the proximal region of the at least partially fused connector termination meets the specification.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/374,185, filed Aug. 12, 2016, the disclosure of which is incorporatedherein by reference in its entirety.

TECHNICAL FIELD

Aspects of the present disclosure relate generally to methods formanufacturing a fused fiber termination, and, specifically, to methodsof using an imaging system to provide feedback during manufacture andfor improving the coupling efficiency of fused fiber terminations.

BACKGROUND

Optical fibers are commonly used in medical applications. Optical fibersmay be used in numerous procedures to act as optical waveguides forcarrying light energy from a laser to a target body region to deliverenergy to the target region. For example, in lithotripsy procedures,optical fibers are delivered through an endoscope—e.g., a cystoscope,ureteroscope, renoscope, or nephroscope—and are used to transmit lightpulses from a laser source to a location within the body to break up andremove urinary stones.

Glass-clad optical fibers are commonly used in medical applications fordelivery of laser energy. The fibers are often terminated withconnectors that allow the optical fibers to couple and uncouple fromlaser delivery systems without compromising the alignment of the opticalfiber system. Traditionally, fiber connector terminations often includedadhesives to secure the optical fiber to the surrounding glass ferrule;however, issues of outgassing caused contamination of the laser outputlens or, in some cases, caused the fiber termination to catastrophicallyfail.

To overcome the outgassing issues, methods of forming connectorterminations were developed that reduced the use of adhesives or avoidedthe use of adhesives altogether. One solution was to directly fuse theoptical fiber core and glass cladding to a surrounding glass ferrule atthe termination to create a monolithic glass end that both secures thefiber to the ferrule and aligns the fiber within the ferrule without theuse of adhesives. To fuse the fiber and the ferrule to one another atthe connector termination, heat may be applied around the sides of theproximal end of the fiber and ferrule and to the proximal face of theconnector termination, as is described in greater detail in U.S. Pat.No. 6,282,349, incorporated herein by reference in its entirety.

Yet, fused connector terminations require precise positioning betweenthe fiber, ferrule, and heat source(s) in order to achieve the desiredgeometries for high coupling efficiency from the laser energy into afiber body. Creating smooth and consistent concave- or convex-shapedconnecter terminations on the proximal face and controlling the fusionof the ferrule and the optical fiber along the sides, both of which areimportant for the coupling efficiency of the manufactured connectortermination, can become an issue with fused connectors. Couplingefficiency is affected by, among other things, (i) the concentricity ofthe optical fiber within the fused ferrule, (ii) the geometry and depthof the concave (or convex) fused terminal surface, (iii) the smoothnessof the fused terminal surface, and (iv) the shape and taper ratio of thetapered fiber, for example.

Currently, there is no way of controlling the fusion process in realtime to ensure that the finished, fused connector termination hassatisfactory coupling efficiency. Instead, heat is applied to the glassfiber and ferrule to fuse them together, and then post-fusioninspections are carried out to determine whether the fused connectormeets manufacturing requirements. This uncontrolled manufacturing methodmay lead to large amounts of waste or manufacturing inefficiencies,because improperly fused connectors must be discarded.

As a result, a need exists for methods of manufacturing fused connectorterminations that allows for tighter control of the fusion process.Specifically, a need exists for a method that allow for real-timeassessment and control of the fusion process to promote increasedcoupling efficiency of the manufactured connectors and reduce waste.

The devices and methods of the current disclosure may rectify some ofthe deficiencies described above or address other aspects of the priorart.

SUMMARY OF THE DISCLOSURE

Aspects of the present disclosure are directed to methods for producinga fused connector termination. An exemplary method may include setting aspecification requirement to be met by the fused connector terminationand applying an amount of heat to a proximal region of an unfusedconnector termination. The proximal region of the unfused connectortermination may comprise an inner optical fiber coaxially positionedwithin an outer ferrule, and applying the amount of heat may at leastpartially fuse the optical fiber to the outer ferrule to form an atleast partially fused connector termination. The method may also includeimaging the proximal region of the at least partially fused connectortermination and determining, based on the imaging, whether the proximalregion of the at least partially fused connector termination meets thespecification.

Various aspects of the method may include one or more of the featuresbelow. The amount of heat may be a first amount of heat and, if theproximal region of the at least partially fused connector termination isdetermined to not meet the specification, the method may furthercomprise applying a second amount of heat to the proximal region of theat least partially fused connector termination, and the imaging step andthe determining step may be repeated after applying the second amount ofheat. The applying step, the imaging step, and the determining step maybe repeated until the proximal region of the at least partially fusedconnector termination is determined to meet the specification. In someaspects, the first amount of heat may be different than the secondamount of heat, or, the first amount of heat may be the same as thesecond amount of heat. The amount of heat may be applied to one or moreof a proximal face of the connector termination and a side of theconnector termination. Imaging the proximal region may include focusingthree or more imaging devices on the proximal region. The one or moreimaging devices may be oriented to view the proximal region along az-axis and at least one of an x-axis and a y-axis, and imaging theproximal region may include focusing one or more imaging devices on atleast two locations on the proximal region. Determining whether theproximal region of the at least partially fused connector terminationmeets the specification may include determining whether at least one ofa diameter, a depth, a curvature, or a surface smoothness of a dishformed on a proximal face of the at least partially fused connectortermination meets the specification based on one or more images of theproximal face captured along a z-axis. In further aspects, the one ormore images of the proximal face may include at least one of an imagefocused on an edge of the dish or an image focused on a central regionof the dish. Determining whether the proximal region of the at leastpartially fused connector termination meets the specification mayinclude determining whether at least one of a depth of heat penetration,extent of fusion of the optical fiber to the outer ferrule, or relativelocation of the optical fiber within the outer ferrule meets thespecification based on one or more images of the proximal regioncaptured along a side of the connector terminal. The one or more imagesof the side of the connector terminal may include at least one of animage focused on an outer surface of the outer ferrule, an image focusedon an inner surface of the outer ferrule, or an image focused on anouter surface of the optical fiber. Imaging the proximal region of theat least partially fused connector termination may be performed using anoptical microscope, and, in some aspects, at least one of an imagingdevice, the connector termination, or a heat source may be moved whenimaging the proximal region of the at least partially fused connectortermination or when applying heat to the proximal region.

In accordance with another aspect, a method for producing a fusedconnector termination may include selecting a specification requirementto be met by the fused connector termination and applying a first amountof heat to a proximal region of an unfused connector termination. Theproximal region of the unfused connector termination may comprise aninner optical fiber coaxially positioned within an outer ferrule, andthe first amount of heat may partially fuse the inner optical fiber tothe outer ferrule at the proximal region. The method may further includeimaging a proximal face of the partially fused connector termination andimaging a side region of the partially fused connector termination.Based on the imaging of the proximal face and the imaging of the sideregion, the method may also include determining where to apply a secondamount of heat to the proximal region of the partially fused connectortermination and applying the second amount of heat to the proximalregion of the partially fused connector termination. The method mayinclude imaging at least one of the proximal face of the partially fusedconnector termination or the side region of the partially fusedconnector termination and determining whether the proximal region of thepartially fused connector termination meets the specification.

In various aspects, applying the first amount of heat may includeapplying heat to the proximal face and to the side region. In someaspects, applying the second amount of heat may include applying heat toone or more of the proximal face and the side region. The first amountof heat and the second amount of heat may be different.

In another aspect of the disclosure, a method for producing a fusedconnector termination may include selecting a specification requirementto be met by the fused connector termination and applying a first amountof heat to a proximal region of an unfused connector termination. Theproximal region of the unfused connector termination may comprise aninner optical fiber coaxially positioned within an outer ferrule, andthe first amount of heat may partially fuse the inner optical fiber tothe outer ferrule at the proximal region. The method may also includefocusing an imaging device on at least one portion of a proximal face ofthe partially fused connector termination and focusing an imaging deviceon at least one portion of a side region of the partially fusedconnector termination. Based on the imaging of the proximal face and theimaging of the side region, the method may also include determining howto apply a second amount of heat to the proximal region of the partiallyfused connector termination and applying the second amount of heat tothe proximal region of the partially fused connector termination. Themethod may further include focusing an imaging device on at least one ofa portion of the proximal face or a portion of the side region anddetermining whether the proximal region of the at least partially fusedconnector termination meets the specification.

Additional objects and advantages of the aspects will be set forth inpart in the description that follows, and in part will be obvious fromthe description, or may be learned by practice of the aspects. It is tobe understood that both the foregoing general description and thefollowing detailed description are exemplary and explanatory only andare not restrictive of the claims.

As used herein, the terms “comprises,” “comprising,” or any othervariation thereof, are intended to cover a non-exclusive inclusion, suchthat a process, method, article, or apparatus that comprises a list ofelements does not include only those elements, but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate the disclosed aspects, andtogether with the description, serve to explain the principles of thedisclosed aspects. In the drawings:

FIG. 1A is a schematic illustration of a fiber connector terminationwith a tapered optical fiber;

FIG. 1B is a schematic illustration of a fiber connector terminationwith a non-tapered optical fiber;

FIG. 2A is a schematic illustration of applying heat to a fiberconnector termination in order to fuse an optical fiber to a glassferrule;

FIG. 2B is a schematic illustration of the fiber connector terminationdepicted in FIG. 2A once the optical fiber has been fused to the glassferrule;

FIG. 3A schematically depicts axes along which one or more imagingdevices may be oriented relative to a fiber connector termination, inaccordance with exemplary aspects of the present disclosure;

FIG. 3B schematically depicts a plurality of imaging devices orientedaround a fiber connector termination for imaging the fiber connectortermination along the axes of FIG. 3A, in accordance with exemplaryaspects of the present disclosure;

FIG. 4A schematically depicts an integrated imaging and fusion systemand connector termination prior to fusion, in accordance with exemplaryaspects of the present disclosure;

FIG. 4B schematically depicts the integrated imaging and fusion systemof FIG. 4A and connector termination after commencement of fusion; and

FIG. 5 is a flow chart depicting steps of an exemplary method for fusinga connector termination, in accordance with an exemplary aspect of thepresent disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to the exemplary aspects of thepresent disclosure described below and illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to same or like parts. Both theforegoing general description and the following detailed description areexemplary and explanatory only and are not restrictive of the features,as claimed. The term “exemplary” is used herein in the sense of“example,” rather than “ideal.” As used herein, the terms “about,”“substantially,” and “approximately,” indicate a range of values within+/−5% of a stated value. The term “proximal” refers to a position closerto the connector end of a fiber connecter termination that couples witha laser source. The term “distal” as used herein refers to a positionfurther from the connector end of a fiber connector termination.

Aspects of the present disclosure are generally drawn to methods forproducing fused connector terminations using integrated imaging systemsto provide real-time feedback and improved control over themanufacturing process. By obtaining real-time feedback, heat may beapplied to the ferrule and fiber incrementally, instead of all at once,to provide increased control over the fusion process, as will bedescribed in detail below in reference to the exemplary aspects.

FIGS. 1A and 1B depict schematic views of standard fiber connectorterminations prior to fusion. FIG. 1A shows a connector termination 8.Connector termination 8 includes an optical fiber 1 having a taperedproximal end 3, and FIG. 1B shows an optical fiber 1 having anon-tapered proximal end 3′. Optical fiber 1 may be formed of, e.g.,silica, and may include one or more layers of cladding, coating(s),and/or protective jacket(s), such as one or more layers of polymer ornylon, surrounding the silica core at a proximal region. In aspects inwhich optical fiber 1 includes cladding, coating(s), and/or jacket(s)comprised of polymeric materials, these polymers may stop short of theproximal end of optical fiber 1, or may be removed from the proximal endof optical fiber 1, prior to fusing optical fiber 1 to ferrule 4.Optical fiber 1 extends from a distal end (not shown) that extends intothe body to proximal end 3. Exemplary optical fibers 1 may range inglass diameter from approximately 100 μm to approximately 1,000 μm.Exemplary glass cladding may range in diameter from approximately 100 μmto approximately 1,100 μm. Exemplary taper diameters, if applicable, mayrange in maximum diameter from approximately 130 μm to approximately 800μm. The exemplary sizes provided herein serve as examples only and arenot restrictive.

Optical fiber 1 is surrounded along at least a portion of its length bya ferrule 4. Ferrule 4 may be formed of, e.g., glass, silica, or quartz.Ferrule 4 may be cylindrical and may have a central opening 6 extendingalong a longitudinal axis of ferrule 4. Opening 6 may be dimensioned toreceive optical fiber 1 within it. Optical fiber 1 may thus fitconcentrically within opening 6 in ferrule 4, so that optical fiber 1and ferrule 4 are aligned coaxial with one another at proximal region 2of connector termination 8. A proximal end of opening 6 extends alongthe longitudinal axis of ferrule 4, or the proximal end of opening 6 maybe chamfered, e.g., flare outwards so that the proximal-most end ofopening 6 is wider than a distal region of opening 6, as is shown inFIGS. 1A and 1B. Exemplary glass ferrules 4 may have an outer diameterof approximately 1,000 μm to approximately 1,700 μm.

As discussed above, a fused fiber connector termination 8 may be formedby fusing optical fiber 1 and ferrule 4 to each other to create anintegral structure at fused region 7 (FIG. 2B) at proximal region 2.FIG. 2A shows arrows H (optional heat source) and H′, which depictrepresentative directions from which heat may be applied to ferrule 4and optical fiber 1 to fuse the two components together. For example,heat may be applied to the proximal face of ferrule 4 and optical fiber1, as shown by arrow H (optional), and heat may be applied to one ormore sides of ferrule 4 and optical fiber 1, as shown by arrow H′.Ferrule 4 and optical fiber 1 may be rotated and/or tilted as heat isapplied to the sides of ferrule 4 and optical fiber 1, the heat may bemoved around the proximal region of ferrule 4 and optical fiber 1, orthe heat may be applied from multiple sides of ferrule 4 and opticalfiber 1 at once, or any suitable combination thereof. FIG. 2B showsfused region 7 formed by the heating of FIG. 2A. Following fusion, aconcave face 5 may be formed on the proximal face of the fused connectortermination. Although a concave face is depicted in FIG. 2B, one ofordinary skill in the art will understand that, depending on theintended use of optical fiber 1, a convex face or a substantially flatface may be formed at the proximal end.

As explained above, standard production of fused terminal connectorsgenerally includes a one-step method of applying heat to proximal region2 of optical fiber 1 and ferrule 4 to create fused region 7. Processverification is typically limited to post-fusion visual inspection toidentify defects and/or determination of system-level transmissionmeasurements once connectorized. Fully assembled fibers are generallythen scrapped if the transmission measurements fail to meet one or morepredetermined specifications. Such one-step methods may provide littlemanufacturing control over the fusion process, and post-processing-onlyevaluation may lead to manufacturing inefficiencies. Further, theinability to control fusion may lead to losses in coupling efficiency.To overcome one or more of these disadvantages, an integrated imagingprocess is described herein.

An exemplary integrated imaging system and method may include one ormore optical imaging devices for viewing proximal region 2 of ferrule 4and optical fiber 1 before, during, and/or after fusion. FIG. 3Aschematically depicts exemplary axes along which one or more imagingdevices may be oriented to view the fusion process and provide feedback.For example, imaging devices may be arranged to view proximal region 2of connector termination 8 along the x-axis and y-axis, as well as fromthe z-axis. Imaging along the z-axis may provide real-time informationabout the formation of the proximal face, including, e.g., the width,depth, curvature, and/or smoothness of the concavity (or, in someaspects, convexity or flatness) of the proximal face. Imaging along thex- and y-axes may provide information about the completeness of fusion(i.e., the penetration depth of the heat and the extent to which opticalfiber 1 and ferrule 4 have become a monolithic structure). Imaging alongthe x- and y-axes may also be used to measure the fiber geometry, sincea glass ferrule 4 may be transparent or opaque, allowing the imagingsystem to focus on optical fiber 1 within central opening 6.Additionally, imaging along the z-, x-, or y-axes may provideinformation about the concentricity and/or alignment of optical fiber 1within opening 6 of ferrule 4.

Although three viewing axes are shown in FIG. 3A, it is contemplatedthat a single viewing axis, two viewing axes, or more than three viewingaxes may be used to provide feedback. Additionally, FIG. 3B depictsimaging devices 10, 10′, and 10″, collectively referred to as imagingdevices 10, which may be oriented to view proximal region 2 along eachof the axes in FIG. 3A. However, if more or fewer viewing axes are used,then more or fewer imaging devices 10 may be used. In some aspects, eachimaging device 10 may be oriented to provide imaging along a singleaxis, for example, the number of viewing axes and the number of imagingdevices may be equal. In such aspects, each imaging device may bestationary along its respective imaging axis. In some aspects, however,one or more imaging devices 10 may be moveable to provide imaging alongmore than one axis. For example, a single imaging device may provideimaging of the proximal face along the z-axis and then may also bemoveable to provide imaging from a side of proximal region 2. In someaspects, some of the imaging devices may be stationary, while otherimaging devices may be moveable. For example, imaging device 10 alongthe z-axis may be stationary, while one or more of imaging devices 10′or 10″ may be moveable along the x- or y-axis. Further, in someexemplary aspects, stationary or moveable imaging devices may beconfigured to tilt relative to connector termination 8. And, whether ornot stationary or moveable imaging devices are used, ferrule 4 andoptical fiber 1 may be moved (e.g., rotated or tilted) relative to theimaging devices and/or heat sources before, during, and/or after thefusion process to provide imaging along different angles or to modifywhere on proximal region 2 heat is applied.

Exemplary imaging systems may include, for example, one or more opticalmicroscopes. An optical microscope may include an objective lens with alight source. The microscope may be focused on different regions of theterminal connector to obtain different views of the proximal region inorder to assess various information about the fusion process, as will bedescribed in detail below. In some aspects, the imaging system may alsoinclude, e.g., a CMOS and/or CCD sensor, or other suitable imagingdevices.

By integrating an imaging system with the process of heating and fusinga connector terminal, incremental heating may be applied to more finelycontrol the fusing of ferrule 4 with optical fiber 1 and the surfaceproperties of the proximal face. By monitoring and controlling thesecharacteristics, coupling efficiency may be improved. As mentionedabove, the primary parameters that affect coupling efficiency include(i) the concentricity of the optical fiber within the fused ferrule,(ii) the geometry, depth, and curvature of the concave or convex fusedterminal surface, (iii) the shape and the tapered ratio of the opticalfiber, and (iv) the smoothness of the fused terminal surface. Forexample, the origin of both the optical fiber and the ferrule should besubstantially the same. This characteristic may be controlled prior toheating, e.g., by positioning optical fiber 1 within opening 6 offerrule 4 and by positioning the proximal region within the integratedimaging and heating system. This characteristic may also be controlledduring heating (e.g., if optical fiber 1 becomes off-centered duringfusion) by tilting or rotating the heating source and/or connectortermination 8 or by applying heat uniformly or non-uniformly around theside of connector termination 8.

Likewise, the diameter and shape of the optical fiber may be controlledprior to heating or may be controlled or affected during heating. Forexample, an optical fiber with a particular shape (e.g., tapered ornon-tapered, or degree of tapering) or particular size may be selectedfor inclusion within opening 6 of ferrule 4. In some aspects, heatingmay be applied to a proximal end of optical fiber 1 as an initial stepor as part of the heat application in order to modify the end of theoptical fiber (e.g., create tapering on a non-tapered fiber or modifythe angle of a tapered fiber).

The geometry, depth, and curvature of the proximal face of the fusedterminal surface may be controlled during the heating process. Ideally,the concave or convex proximal surface should behave like an opticallens, with the refraction affecting the location of the focal point. Thesmoothness and shape of the terminal surface may also be controlledduring the heating process to improve coupling efficiency by reducingscattering loss. By providing feedback from an integrated imagingsystem, heat application may be controlled to provide a smootherterminal surface. By reducing surface roughness, light scattering may bereduced, and thus less light energy may be lost by the optical fiberduring use.

Thus, by providing feedback, heat application may be controlled andincrementally applied in order to control the parameters of theconnector termination that affect coupling efficiency, thereby improvingcoupling efficiency.

In one exemplary method, a connector termination 8 having an opticalfiber 1 within opening 6 of ferrule 4 may be situated within anintegrated imaging and fusion system 9, as shown in FIG. 4A. One or moreimaging devices 10 may be located around proximal region 2 of opticalfiber 1 and ferrule 4 and may be focused on proximal region 2. One ormore heat sources H, H′ may be located adjacent proximal region 2. Forexample, heat source H may be directed towards the proximal face offiber 1 and ferrule 4, and one or more heat sources H′ may be directedtowards a side of proximal region 2. In some aspects, a single heatsource may be moved during the fusion process to apply heat to both theproximal face and a side of proximal region 2. Or, heat source H may bedirected towards the proximal face, and one or more heat sources H′ maybe directed towards a side of proximal region 2, and the one or moreheat sources H′ may be moved around a circumference of ferrule 4.Alternatively or additionally, proximal region 2 may be rotated ortilted relative to the heat source(s) in addition to or instead ofmovement of the one or more heat sources.

Exemplary heat sources may include, e.g., laser energy (such as a CO₂laser ranging from between about 1 to 500 W), electric arc discharge (ofsimilar wattage), and/or a flame. These heat sources may be orientedsubstantially perpendicular to optical fiber 1 and ferrule 4 (H′), orlongitudinally to the optical fiber (H). The heat source(s) and/oroptical fiber 1 and ferrule 4 may or may not be rotated or tiltedrelative to one another.

In some aspects, integrated imaging and fusion system 9 may be arrangedso that placing connector termination 8 within the integrated systemautomatically positions connector termination 8 relative to the imagingdevice(s) and/or heat source(s). For example, a holder or clamp mayposition connector termination 8 relative to imaging devices 10. Inother aspects, one or more of connector termination 8, the imagingdevice(s), and/or the heat source(s) may be moved and/or positionedrelative to one another. Additionally, in some aspects, the positioningof the various components relative to one another may be pre-set or maybe predetermined based on, e.g., one or more of the size of theconnector termination, the intended use of the connector termination,the type of materials that make up the ferrule and/or the optical fiber,the required specifications of the finished connector termination, theintended shape (e.g., convex or concave proximal face) of the finishedconnector termination, the type of heat source used in the system, theamount of heat to be applied, or any suitable combination thereof. Insome aspects, an operator may input the relevant information into theintegrated system, and the integrated system may automatically adjustthe relative positioning and location of the various components. In someaspects, an operator may input the relative positioning and location ofthe various components and then the system may automatically make theadjustments. In such exemplary aspects, system 9 may include one or moreprocessors 12 in order to store and/or calculate specifications and/orpositioning information and/or to control positioning of the relativecomponents. In some aspects, an operator may position and locate thecomponents relative to one another manually.

In exemplary aspects, system 9 may include a user interface forinputting information into the system, e.g., a keyboard, touch screen,levers, buttons, knobs, or other suitable input devices or combinationsof input devices for controlling or adjusting the settings, inputtingpredetermined specifications, and/or inputting information about theparticular connector termination 8 and/or its intended use. System 9 mayalso include a display device for outputting one or more of the imagingfeedback captured by the imaging device(s), information regarding thepredetermined specifications input into the system, informationregarding the quality of the connector termination being manufactured,information regarding the status of the fusion process, or any othersuitable output. The display device may include a monitor, a screen, aseries of lights, or other suitable visual indicators or combinationsthereof. Components of system 9, e.g., one or more imaging devices, heatsources, user interfaces, display devices, and/or processors 12 may becoupled to each other via wireless or wired connections, or acombination thereof.

Once the components are in place, heat may be incrementally applied toconnector termination 8 to fuse ferrule 4 and optical fiber 1 together.In one exemplary aspect, a first amount of heat may be applied toproximal region 2 of connector termination 8. Heat application may occurautomatically according to the programing and specifications input intosystem 9, or may be manually triggered by an operator.

FIG. 4B schematically depicts a connector termination 8 that has begunfusing after the application of heat. After applying the first amount ofheat, imaging device(s) 10 may image connector termination 8 and providefeedback to system 9. For example, pre-set process specifications,measurements, and tolerances for the finished, fused connectortermination 8 may be determined and input into system 9 at the outset ormay be programmed or stored in processor 12. One or more imaging devicesmay focus on and image different aspects of connector termination 8after the first application of heat (and/or after subsequentapplications of heat) in order to assess how the fusion is progressingrelative to the predetermined specifications.

For example, an imaging device oriented along the z-axis may be used toassess whether the proximal face of connector termination 8 is formingin accordance with the predetermined specifications. The imaging devicemay provide feedback regarding, e.g., the smoothness of the surface. Insome aspects, a concave or convex proximal face of a specific diameter,curvature, and depth may be desired. The imaging device oriented alongthe z-axis may be focused on one or more locations on the outer edge ofthe concave or convex dish to assess, e.g., diameter size,circumference, or uniformity of dish shape. The imaging device may alsobe focused on a central portion of the dish, and the images of the outeredge and of the central portion may together provide information aboutthe depth and/or curvature of the concave or convex dish. Thisinformation may be relayed to processor 12 of system 9, which may thenuse this imaging feedback to decide in real time how much heat to applynext, where the heat should be applied next, at what angle the heatshould be applied, or whether no additional heat should be applied,depending on how the imaging feedback and observed measurements comparedto the predetermined specifications (e.g., within or outside of apredetermined acceptability range).

For example, if the imaging feedback indicated that the depth of aconcave portion of the proximal face fell short of the predeterminedspecifications, then additional heat may be applied to a side portion ofconnector termination 8 in order to increase the depth of the concavity.In some aspects, the depth of the dish may need to meet a specificationranging within approximately sub-microns to approximately 500 μm. Insome aspects, if the imaging feedback indicates that the dish shape isnot symmetrical, then heat may be applied at an angle, either by tiltingthe heat source and/or by tilting connector termination 8. In someaspects, if the imaging feedback indicates that the surface finish ofthe proximal face is not smooth enough, or indicates that the diameterof the concave or convex dish is too small, additional heat may beapplied along the z-axis in order to smooth the surface finish of theproximal face and/or increase the size of the dish. In some aspects, thesize of the dish may need to meet a specification ranging withinapproximately 50 μm to approximately 1,700 μm. If the proximal facemeets the predetermined specifications, then no additional heat may beapplied to the proximal face along the z-axis.

In some aspects, an imaging device located along the z-axis may use oneor more of bright field and dark field imaging modalities. For example,bright field imaging may be used to measure depth, size, geometry, orother similar characteristics of the proximal face. Dark field imagingmay be used to measure, e.g., roughness and finish of the surface of theproximal face. For example, dark field imaging may block out directlytransmitted light from the center of the field, allowing for detectionof only light entering the imaging device from around the edges so thatthe imaging device detects only scattered light. In some aspects, theimaging device may be switched between bright-field and dark-fieldimaging modalities.

In some aspects, one or more imaging devices located around a side ofproximal region 2 may be focused on one or more of an outer surface offerrule 4, an inner surface of ferrule 4 defining opening 6, or on anouter surface of optical fiber 1 within ferrule 4 (which may be visibledue to the transparency of surrounding ferrule 4). One of these imagesmay be captured individually, or a combination of images may be capturedand compared relative to one another. The one or more images may berelayed in real time to processor 12 of system 9 to assess progress offusion between optical fiber 1 and ferrule 4. For example, the imagesmay be used to assess one or more of the depth of heat penetrationduring the application of heat, the extent to which optical fiber 1 andferrule 4 have fused together, the relative spacing or concentricity ofoptical fiber 1 within ferrule 4, and/or whether this spacing orconcentricity has been affected by the fusion process. This imaginginformation may then be used to determine whether additional heat shouldbe applied, if so, how much heat should be applied, and at what angle orposition to apply additional heat. For example, if adequate fusion ofoptical fiber 1 and ferrule 4 has not been achieved, additional heat maybe applied substantially uniformly around the sides of proximal region2. If the angle or positioning of optical fiber 1 within ferrule 4 doesnot meet the predetermined specifications, then additional heat may beapplied at an angle relative to the outer surface of ferrule 4 (e.g.,not perpendicular to the outer surface) or to one portion of proximalregion 2.

In some aspects, the images captured and assessments made may change asadditional heat is applied. For example, once one characteristic of theconnector termination falls within the predetermined specifications,then images to assess that characteristic may no longer be capturedafter additional rounds of heating. In some aspects, each characteristicassessed may continue to be assessed as additional rounds of heating areapplied, even if one or more characteristics have been observed asmeeting the predetermined specifications based on the feedback imaging.For example, the characteristics may continue to be assessed in order toconfirm that the additional rounds of heating have not caused thecharacteristic to fall outside of the predetermined specifications. Insome aspects, a final set of images may be obtained after allcharacteristics have been found to meet the predetermined specificationsin order to provide one last holistic quality assessment of eachcharacteristic of the fused connector termination.

In aspects utilizing more than one imaging device, the imaging devicesmay each provide feedback to system 9, and processor 12 may combineand/or compare the imaging information to determine whether the fusionof connector termination 8 meets the predetermined specifications. Inaspects utilizing one imaging device, for example, an imaging devicethat is moved relative to proximal region 2 to image different portionsof connector termination 8 (e.g., a proximal face and a side region),the imaging device may be positioned around connector termination 8 andfeedback from each relative position may be relayed to processor 12. Or,in some aspects, only one imaging device may be used, e.g., to assesseither a proximal face or a side portion of connector termination 8.

The heat application and imaging steps may be performed and repeated asmany times as necessary until the fused connector termination 8 meetsthe predetermined specifications.

During heat application, heat may be applied optionally to a side ofproximal region 2 or to the proximal face, or the heat may be appliedsimultaneously to both the side and the proximal face. For example, heatmay be applied uniformly from all directions at the same time or may beapplied from one side then another or from only the top along the z-axisor from only the side along the x- and/or y-axis. To achieve uniformfusion, one or more heat sources may be moved around proximal region 2,and/or connector termination 8 may be rotated relative to the heatsource(s). In each subsequent round or rounds of heat application, heatmay be applied according to the imaging feedback received. For example,if the imaging feedback indicates that the proximal face meetspredetermined specifications, then no additional rounds of heating maybe applied along the z-axis. If the imaging feedback indicates that thefusion of optical fiber 1 and ferrule 4 meets the predeterminedspecifications, then no additional rounds of heating may be applied to aside region. In some aspects, however, even if the fusion of fiber 1 andferrule meets the predetermined specifications, but the curvature of theproximal face is too deep, then additional heat may be applied to theside of proximal region 2 in order to create a shallower curvature.Accordingly, whether additional heat is applied to a given location, theamount of additional heat applied to a given location, and/or thedirection from which heat is applied to a given location may depend onimaging feedback received from that particular location or may depend onimaging feedback received from a different location of the connectortermination, or both.

In some aspects, the same amount of heat may be applied during eachround of heat application. In other aspects, the amount of heat insubsequent rounds of heat application may be determined, at least inpart, in real-time based on the feedback, e.g., the amount by which acharacteristic of the imaged connector termination 8 deviates from thepredetermined specifications. If greater deviations from thespecifications are detected by the imaging devices, then more heat maybe applied, and/or heat may be applied for a longer duration of time. Ifsmaller deviations are detected, then less heat may be applied, and/orheat may be applied for shorter durations of time.

In some aspects, the method of producing a heat-fused connectortermination 8 may further include shaping the proximal end of opticalfiber 1 prior to fusion. For example, as is shown in FIGS. 1A and 1B,either a tapered or a non-tapered optical fiber 1 may be used to form afused connector termination 8. In some aspects, the production methodmay include first applying heat to the proximal region of a non-taperedoptical fiber 1 in order to first create a tapered shape. In otheraspects, a non-tapered optical fiber 1 may be used, and the initialtapering step may not be included. In still other aspects, a taperedoptical fiber may be used and the initial tapering step may not beincluded. In other aspects, a tapered optical fiber may be used and theinitial tapering step may be included to change the angle of taper atthe proximal end of the optical fiber.

FIG. 5 depicts a summary of the basic method according to an aspect ofthe present disclosure. First, specifications for a finished fusedconnector termination may be set prior to commencement of the fusionprocess, shown as step 20. Next, at step 21, an amount of heat may beapplied to the proximal region of the connector termination. After theheat is applied, the proximal region of the connector termination may beimaged, step 22. If step 23 is reached and the imaging feedbackindicates that the proximal region of the connector termination meetsthe specifications, then the method stops (step 24) and no additionalheat is applied to the proximal region. If step 25 is reached and theimaging feedback indicates that the proximal region of the connectortermination does not meet the specifications, then step 21 is repeatedand another round of heat is applied to the proximal region of theconnector termination. The proximal region of the connector terminationis then imaged again (step 22). Rounds of heating and imaging may berepeated as necessary until the images indicate that the proximal regionof the connector termination meets the specifications.

In exemplary aspects, this method may deliver small amounts of heatincrementally, with imaging feedback obtained after each round ofheating. For example, 50% of the amount of heat applied in prior,one-shot methods may be applied during each incremental heat applicationin exemplary methods described herein. In some aspects, the amount ofheat delivered during each round of heating may further decrease. Forexample, 50% heat may be delivered to the connector termination, imagingfeedback may be received, 20% heat may be delivered to the connectortermination, imaging feedback may be received, 10% heat may be deliveredto the connector termination, imaging feedback may be received, and soon until the connector termination falls within the range of presetspecifications. The percentages provided are exemplary only, but areoffered to further illustrate aspects of the disclosure.

Aspects of the present disclosure may improve coupling efficiency ofproduced connector terminations and thus increase the amount of energythat may ultimately be delivered by the optical fiber during medicalprocedures. In aspects in which the produced connector termination isused during a lithotripsy procedure, e.g., the amount of energydelivered to target tissue and/or a urinary stone may be increased. Thismay have the beneficial effect of reducing overall procedure times fortreatment of a given volume or density of stone. For example, byreducing energy loss along the optical fiber, more energy may bedelivered in a given amount of time, and thus, if a certain amount ofenergy is required to break up a stone, then a connector terminationwith increased coupling efficiency may be able to break up the stone ina shorter amount of time. Further, a connector termination with improvedcoupling efficiency may be able to accommodate a broader variety oflaser console designs. For example, laser consoles with poorer beamquality may still provide sufficient energy if used with a connectortermination having a higher coupling efficiency due to thermal lensing.Exemplary aspects may also decrease manufacturing waste by providingreal-time, in-situ, quality control to reduce the number of finishedconnector terminations produced that do not meet predeterminedspecifications.

The many features and advantages of the present disclosure are apparentfrom the detailed specification, and thus, it is intended by theappended claims to cover all such features and advantages of the presentdisclosure that fall within the true spirit and scope of the disclosure.Further, since numerous modifications and variations will readily occurto those skilled in the art, it is not desired to limit the presentdisclosure to the exact construction and operation illustrated anddescribed, and accordingly, all suitable modifications and equivalentsmay be resorted to, falling within the scope of the present disclosure.

Moreover, those skilled in the art will appreciate that the conceptionupon which this disclosure is based may readily be used as a basis fordesigning other structures, methods, and systems for carrying out theseveral purposes of the present disclosure. Accordingly, the claims arenot to be considered as limited by the foregoing description.

What is claimed is:
 1. A method for producing a fused connectortermination, the method comprising: setting a specification requirementto be met by the fused connector termination; applying an amount of heatto a proximal region of an unfused connector termination, wherein theproximal region of the unfused connector termination comprises an inneroptical fiber coaxially positioned within an outer ferrule, and whereinapplying the amount of heat at least partially fuses the optical fiberto the outer ferrule to form an at least partially fused connectortermination; imaging the proximal region of the at least partially fusedconnector termination; and based on the imaging, determining whether theproximal region of the at least partially fused connector terminationmeets the specification.
 2. The method of claim 1, wherein the amount ofheat is a first amount of heat; wherein, if the proximal region of theat least partially fused connector termination is determined to not meetthe specification, the method further comprises applying a second amountof heat to the proximal region of the at least partially fused connectortermination; and wherein the imaging step and the determining step arerepeated after applying the second amount of heat.
 3. The method ofclaim 2, wherein the applying step, the imaging step, and thedetermining step are repeated until the proximal region of the at leastpartially fused connector termination is determined to meet thespecification.
 4. The method of claim 2, wherein the first amount ofheat is different than the second amount of heat.
 5. The method of claim2, wherein the first amount of heat is the same as the second amount ofheat.
 6. The method of claim 1, wherein the amount of heat is applied toone or more of a proximal face of the connector termination and a sideof the connector termination.
 7. The method of claim 1, wherein imagingthe proximal region includes focusing three or more imaging devices onthe proximal region.
 8. The method of any of claim 7, wherein the one ormore imaging devices are oriented to view the proximal region from az-axis and at least one of an x-axis and a y-axis.
 9. The method ofclaim 1, wherein imaging the proximal region includes focusing one ormore imaging devices on at least two locations on the proximal region.10. The method of claim 1, wherein determining whether the proximalregion of the at least partially fused connector termination meets thespecification includes determining whether at least one of a diameter, adepth, a curvature, or a surface smoothness of a dish formed on aproximal face of the at least partially fused connector terminationmeets the specification based on one or more images of the proximal facecaptured along a z-axis.
 11. The method of claim 10, wherein the one ormore images of the proximal face include at least one of an imagefocused on an edge of the dish or an image focused on a central regionof the dish.
 12. The method of claim 1, wherein determining whether theproximal region of the at least partially fused connector terminationmeets the specification includes determining whether at least one of adepth of heat penetration, extent of fusion of the optical fiber to theouter ferrule, or relative location of the optical fiber within theouter ferrule meets the specification based on one or more images of theproximal region captured along a side of the connector terminal.
 13. Themethod of claim 12, wherein the one or more images of the side of theconnector terminal include at least one of an image focused on an outersurface of the outer ferrule, an image focused on an inner surface ofthe outer ferrule, or an image focused on an outer surface of theoptical fiber.
 14. The method of claim 1, wherein imaging the proximalregion of the at least partially fused connector termination isperformed using an optical microscope.
 15. The method of claim 1,wherein at least one of an imaging device, the connector termination, ora heat source is moved when imaging the proximal region of the at leastpartially fused connector termination or when applying heat to theproximal region.
 16. A method for producing a fused connectortermination, the method comprising: selecting a specificationrequirement to be met by the fused connector termination; applying afirst amount of heat to a proximal region of an unfused connectortermination, wherein the proximal region of the unfused connectortermination comprises an inner optical fiber coaxially positioned withinan outer ferrule, and wherein the first amount of heat partially fusesthe inner optical fiber to the outer ferrule at the proximal region;imaging a proximal face of the partially fused connector termination;imaging a side region of the partially fused connector termination;based on the imaging of the proximal face and the imaging of the sideregion, determining where to apply a second amount of heat to theproximal region of the partially fused connector termination; applyingthe second amount of heat to the proximal region of the partially fusedconnector termination; imaging at least one of the proximal face of thepartially fused connector termination or the side region of thepartially fused connector termination; and determining whether theproximal region of the partially fused connector termination meets thespecification.
 17. The method of claim 16, wherein applying the firstamount of heat includes applying heat to the proximal face and to theside region.
 18. The method of claim 16, wherein applying the secondamount of heat includes applying heat to one or more of the proximalface and the side region.
 19. The method of claim 16, wherein the firstamount of heat and the second amount of heat are different.
 20. A methodfor producing a fused connector termination, the method comprising:selecting a specification requirement to be met by the fused connectortermination; applying a first amount of heat to a proximal region of anunfused connector termination, wherein the proximal region of theunfused connector termination comprises an inner optical fiber coaxiallypositioned within an outer ferrule, and wherein the first amount of heatpartially fuses the inner optical fiber to the outer ferrule at theproximal region; focusing an imaging device on at least one portion of aproximal face of the partially fused connector termination; focusing animaging device on at least one portion of a side region of the partiallyfused connector termination; based on the imaging of the proximal faceand the imaging of the side region, determining how to apply a secondamount of heat to the proximal region of the partially fused connectortermination; applying the second amount of heat to the proximal regionof the partially fused connector termination; focusing an imaging deviceon at least one of a portion of the proximal face or a portion of theside region; and determining whether the proximal region of the at leastpartially fused connector termination meets the specification.